Decorative materials such as plastic decorative laminates are generally comprising a substrate, such as plywood or steel, overlaid with a decorative sheet having a single printed and/or colored film or a laminate thereof. The laminate type decorative sheet usually comprises a transparent surface layer and a printed and/or colored layer, which are bonded with each other via, if necessary, an adhesive layer. The decorative sheet is used in the form of a laminate on a substrate such as plywood with an adhesive layer therebetween.
The surface layer or the printed and/or colored layer usually contains an ultraviolet absorber (UV absorber) as a weatherability assistant to prevent the printed and/or colored layer from fading or to prevent the whole sheet from deterioration by light during use.
Vinyl chloride resins have been used widely as a base resin of the decorative sheet for their, excellent design properties and proccessability but have recently been being replaced with polyolefin resins from considerations of hydrogen chloride gas by-produced in thermal disposal after use and the material of incinerators. Being nonpolar, however, polyolefin resins have poor compatibility with UV absorbers, which have high polarities. Therefore, if an UV absorber is added to polyolefin resins in an amount effective for preventing fading or deterioration, cases are often met with in which the UV absorber blooms to the surface of the decorative sheet during sheet formation or subsequent fabrication, which not only deteriorates the appearance of the decorative sheet but also contaminates equipment such as a mold and rolls. Further, the UV absorber tends to fail to accomplish its object due to the blooming loss.